Paper feed mechanism for recorders



Nov. 24, 1953 B. G. BLACKMAN ET AL PAPER FEED MECHANISM FOR; RECORDERSFiled April 17, 1950 INVENTORS AND B. G. BLACKMAN A 0. a 0. W m u m m mwnmlumunr hm |||l ll D. O. NELSON ATTORNEY Patented Nov. 24, 1953 PAPERFEED MECHANISM FOR RECORDERS Birt G. Blackman and Donald 0. Nelson, LosAngeles, CaliL, assignors to Bendix Aviation Corporation, South Bend,11111., a corporation of Delaware Application April 17, 1950, Serial No.156,286

3 Claims; 1

This invention relates to recording instruments in which a paper tape isfed from a supply spool past a recording station to a take-up spool, andhas to do particularly with a mechanism for driving or moving the tape.More specifically, the invention relates to that type of mechanism inwhich the tape must be positively fed at a uniform speed, and thetake-up spool has flanges for contacting the edges of the tape andmaintaining the tape in a fixed path as it feeds past the recordingstation,

An object of the invention is to provide a tapedriving mechanism,adapted to be positioned between the recording station and take-upspool, that pulls the tape positively at a constant speed past therecording station and delivers it to the flanged take-up spool, withoutimparting a lateral force to the tape that would interfere with itslateral guidance by the flanges of the take-up spool.

Other more specific objects and features of the invention will appearfrom the description to follow of a preferred embodiment thereof.

In many recorders for making continuous recordings on a paper tape, itis important that the tape he moved at a constant speed past therecording station and be maintained in a fixed lateral position at therecording station. One known method of accomplishing this is to pull thetape past the recording station by passing it between a pair of toothedor knurled rollers one of which is positively driven at a desired speed,and drawing the tape from the rollers onto a flanged spool which isyieldably driven to roll up the tape only as fast as it is delivered bythe feed rollers. It has been found in practice that even with thegreatest care in the manufacture of the drive rollers, as previouslydescribed, they sometimes tend to feed the paper faster near one edgethan the other, thereby tending to cause the paper to ride laterally outof its desired path. The flanges on the take-up spool are supposed toprevent any such lateral wandering of the tape, but in practice,particularly with some types of paper tapes, the strength of the tape isinsufficient to overcome the lateral force applied thereto by thedriving rollers, with the result that the edge of the paper is forcedagains one flange of the take-up spool so strongly that it tears orfolds at the edge as it winds onto the take-up spool.

In accordance with the present invention this tendency toward lateralmovement of the tape by the drive rollers is overcome by providing oneof the drive rollers with a narrow knurled midsection, and slightlyrecessing the end portions of the roller. This applies the main drivingforce over a narrow area near the center of the tape and does not tendto wind one edge of the tape faster than the other, the flanges on thetake-up spool being free to exert their proper centering effect on thetape without impressing forces on the edge of the tape that might damageit. An application of the invention will now he described in detail withreference to the drawing, in which:

Fig. l is a perspective view showing the tape feed mechanism of a depthrecorder.

Fig. 2 is a, detail view, partly in section, of the drive rollers of therecorder, the view being taken in the plane IIII of Fig. l; and

Fig. 3 is a cross section taken in the plane IIIIII of Fig. '2.

Referring to Fig. l, the recorder shown therein comprises a frame plateiii, across the front of which a paper record tape 1 l is drawn. Thistape is fed from a supply roller (not shown) around an idler roller 12positioned at the right edge of the plate It, across the front of theplate back of a ring-type stylus carrier I3, thence around an idlerpulley H! at the left edge of the plate 10. Thereafter the paper isdrawn around a first feed roller l5, then between the feed roller is anda second feed roller 16, then around the feed roller l6 and onto atake-up spool ll having flanges I8 and I!) at its opposite ends, whichare spaced apart approximately the width of the tape 8 I.

In the particular recorder shown, the ring type stylus I4 is constantlyrotated, and a stylus 29 is periodically energized to produce a line 2|on the paper tape. However, the particular construction of the recordingmechanism does not constitute a part of the present invention and willnot be further described.

The drive roller I6 is positively driven at constant speed. Thus, itssupporting shaft 22 extends through a bearing journal in an upper frameplate 23 and has on its upper end a worm wheel 24 that meshes with aworm 25 on the shaft 26 which is driven through a gear train consistingof gears 28 and 29 from the shaft 30 of a motor 21. In the particularrecorder shown, the motor shaft 30 is extended through the front platel0 and carries a drive pinion 32 which meshes with gear teeth on thestylus carrier [3 to rotate the latter.

As best shown in Fig. 2, the lower end of the shaft 22 of the roller I6is journaled in a bearing in a lower frame plate 33 so that the rollerI6 is supported in fixed relation as nearly perpendicular as possible tothe path of the paper tape ll The idler roller l5 has a shaft 34 whichis mounted in slots 35 and 36 in the frame plates 23 and 33 respectivelyso that the roller l5 has freedom of movement toward and away from theroller IS. The idler roller I5 is yieldably urged toward the driveroller 16 by tension springs 38 and 39 which extend around pulleys 40and 4! which are mounted by hearings on opposite ends i the shaft M. Theends of the tension springs 38 and 39 are engaged by adjusting screws 42which extend through cars 43 projecting from the frame plates 23 and 33.

The take-up spool I! is driven by a pulley 45 on the lower end of thespool shaft below the frame plate 33, which pulley is linked by ahellcal tension spring belt 4'! to a drive pulley 48 on the lower end ofthe shaft 22 of the drive roller IE. The pulley 43 always rotates fasterthan the pulley 45, and the spring 41 slips as necessary to maintain aconstant take-up torque on the spool 11.

The mechanism so far described is old and. in this old structure boththe drive roller l5 and the idler roller it had meshing teeth orserration extending their full lengths. The present invention residessolely in the provision of only a small serrated portion its on thedrive roller l6, near its center, as best shown in Fig. 2. Theserrations in the zone lfia of roller 16 mesh with the full lengthserrations of the idler roller l5 and tend to crinkle the paper as itpasses between the rollers, as shown in Fig. 3. This provides such apositive engage "sent between the rollers and the paper that sli pagetherebetween is practically impossible. However, since the drive isapplied substantially only at the center portion of the paper tape, itcannot tend to pull one edge or the tape faster than the other.Therefore the tape flows from the drive roller 16 onto the take-up spooll'l between the flanges l3 and i9 thereon.

It is found in practice that if for any reason the tape tends to ridemore heavily against one flange of the take-up spool, say the flange IB, the lateral thrust of the flange against the edge of the tape issuflicient to start moving away from the flange, and this movement notinterfered with by the drive rollers. The result is that before anypressure on the edge of the tape sufficient to it can result, thealinement of the paper between the flanges of the take-up spool isrestored.

As shown in Fig. the smooth portions 16b on opposite sides of thecentral serrated portion lea oi the roller 16 are recessed to eliminatethe serrations, and are therefore of slightly smaller average diameters.The result is that as it is wrapped around the drive roller IS the tapetends to become concave on the side next to the roller Although for thepurpose of explaining the invention, a particular embodiment thereof hasbeen shown and described, obvious modifications will occur to a personskilled in the art, and we do not desire to be limited to the exactdetails shown and described.

We claim:

1. A tape pulling mechanism for drawing a tape past a predeterminedposition and maintaining lateral alinement of the tape at said position,said mechanism comprising: a flanged take-up spool having flanges spacedthe width of the tape, means rotatably supporting said spool in spacedrelation to said predetermined position, and means for applying torqueto said spool to wind up tape delivered thereto; a pair of feed rollerspositioned between said spool and said position adapted to engage saidtape therebetween; means for urging said rollers together to grip thetape therebetween; and means for positively rotating one of said rollersto feed the tape at a desired speed; in which one of said rollers has aperipheral surface of uniform dieuieter extending the full width of saidtape, and the other roller has a central periph a1 surface zone ofuniform diameter and subs h than said tape and has zones of lesser,uniform diameter extending from the margins of said central zone to theends of the roller, said central peripheral surface zone being shorterthan said zones of lesser diameter.

2. A mechanism according to claim 1 in which said peripheral surface ofsaid one roller is 5&1"- rate and said central zone of said other rollerhas serrations intermeshing with the serrations of said one roller.

3. A mechanism according to claim 1 in which the axes of said rollerslie in. a plane approximately normal to a plane extending from saidpredetermined position to said talre-up spool, and said tape wrapsaround one roller prior to its passage between the rollers, and wrapsaround the other roller following its passage therebetween.

IRT G. BLACKMAN. DONALD O. NELS Ol' l.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 1,153,843 Greene Sept. 14%, 1915 1,331,242 Convery Feb. 17,19:; 2,059,879 La Pierre Nov. 3, 1935 2,325,063 Krueger July 27, 19432,408,320 Kuhlik Sept. 24%, 19-16 2,454,021 Wilson Nov. 16, ill l82,532,563 Markle Dec. 5, 1950 2,564,274 Pratt et a1. Aug. l l, 1051FOREIGN PATlllliS Number Country Date 27,486 Great Britain Dec. 30, 189B

